Restyling quotation marks in Reddle Theme

May I restyle the quotation mark graphic used in blockquotes for the Reddle Theme? I've searched the forums for this and can't find anything that specifically references the bold, black quotation marks, nor can I isolate them when I examine the page with the CSS tool in Firefox. They look terrible with the way I have customized my theme and the CSS I tried to target resulted in absolutely no change. Thank you so much for any help you can offer.